This invention relates to a clamping and feeding device for workpieces which are to be cut with a cold saw (such as a bow saw, a cold circular saw or a band saw) and which are positioned on a machine table at least during the cutting operation. The device has facing, cooperating clamping jaws, at least one of which can be adjusted (and tightened) throughout the possible cross-sectional range of the workpieces. The device further has at least one power-driven feed roller which has a rotary axis oriented transversely to the direction of feed and which, in the zone of the clamping jaws, engages the workpiece for advancing the same into the operational range of the saw component of the sawing machine. The device is, in addition, provided with a stop for limiting the workpiece feed.
In a device of the above-outlined known type the pairwise arranged rollers simultaneously serve as the clamping jaws, that is, they replace the usual clamping jaw faces. The rollers constituting one of the clamping jaws are power driven. This mechanism is so arranged that the clamping jaws are not moved away from one another even during the feeding phase of the workpiece. Consequently, the workpiece feed on the machine table is effected under the full clamping pressure. This results in significant force losses and frictional losses. For the purpose of reducing the frictional losses between the workpiece and the machine table it is feasible to arrange the roller way that supplies the workpieces in a slightly elevated manner. It is, however, the result of such an arrangement that the last workpiece, because of the absence of a rear counterweight, slides forwardly and downwardly during the sawing operation, so that oblique cut surface will result.
Further, in conventional planar clamping jaws and workpiece feed devices that have a second clamping jaw pair (which may be displaceable in the direction of feed), it is an inconvenient phenomenon that the workpiece, as the number of incremental feed steps increases, wanders upwardly between the clamping jaws which again results in oblique cuts.